where \(\underline{\theta }=(\theta _1,\theta _2)\in \Theta =\Re ^2 \,(\Re _{++}^2)\)  is the vector of unknown location (scale) parameters and \(f(\cdot ,\cdot ) \)  is a specified pdf on \(\Re ^2\) ; here \(\Re ^2=(-\infty ,\infty )\times (-\infty ,\infty )\,(\Re _{++}^2=(0,\infty )\times (0,\infty ))\) . In many real life situations ordering between the parameters \(\theta _1\)  and \(\theta _2\)  may be known apriori (say, \(\theta _1\le \theta _2\) ) and it may be of interest to estimate \(\theta _1\)  and \(\theta _2\)  (see, for example, [1]}, [2]}, [3]}, [4]}, [5]} and references cited therein).
